Drill bit is an anti-wear part of conventional equipment used in petroleum drilling, geological drilling and tunnel engineering. It usually contacts with rocks, etching solutions and other impurities directly, and achieves the aim of drilling by rubbing, impacting and scouring. Work performance of drill bit directly influences drilling quality, drilling efficiency and drilling cost.
At present, in the field of boring industry and road construction engineering, roller bit and polycrystalline diamond compact (PDC) bit are widely used, but they still have some problems that are hard to be overcome. In the art, roller bit is usually made from conventional tungsten-cobalt alloy. Although conventional tungsten-cobalt alloy has specific corrosion resistance of hard alloy, between the hardness and strength of which poses a contradiction, that is, roller bit cannot combine good wear resistance and impact toughness; therefore, in practice, mechanical properties of which cannot meet the requirements of severe working conditions, which greatly shortens the service life of the roller bit. For PDC bit in the art, cast iron or steel casting are usually chosen as the substrate material, polycrystalline diamond compact are cladded or welded to the surface of the substrate as wear resistance hardface layer. The substrate is generally obtained by casting or machining, then subjected to hardface processing by thermal spraying thereafter. The technology is often complicated and the cost is relatively high. In addition, in practice drilling operation, if there is foreign body at the bottom of the hole, broken gear or hot friction will happen to PDC bit. As the temperature rises, the carcass is burned, and even the brazing layer is melted, resulting in a missing tooth, which affects the penetration rate and accelerates the failure of the drill bit.
Therefore, a drill bit that has good wear resistance and impact toughness as well as good corrosion resistance and fatigue resistance is in urgent need in the art.